Sejong University Research Team Identifies Dark Matter Through Galactic Warps

Analyzing the Influence of Dark Matter Halos Through Galactic Warps

Sejong University announced on November 12 that Professor Jiwoong Bae's research team from the Division of Liberal Studies has identified the gravitational influence of dark matter halos surrounding galaxies-previously considered unobservable-by analyzing galactic disk warps and the spatial distribution of satellite galaxies.

Professor Jiwoong Bae's research team at Sejong University identified the influence of dark matter halos using the galaxy 'Warp'. Sejong University

This research was jointly conducted by Professor Jiwoong Bae, who served as the first author, along with teams from the University of Oxford in the United Kingdom and Yonsei University in Korea.

The research team presented observational statistics supporting the so-called "glocal effect," which posits that local evolution at the galactic level is closely linked to the global environment of the cosmic large-scale structure. The findings were published in the Astrophysical Journal, the journal of the American Astronomical Society, on November 5.

Among many disk galaxies, including the Milky Way, approximately 60% exhibit warps in their outer disks, bending in S-shaped or U-shaped forms. However, previous explanations based solely on tidal interactions with neighboring galaxies have not sufficiently accounted for the observed frequency and diversity of these warp shapes.

The team focused on the hypothesis that non-spherical and asymmetric dark matter halos exert anisotropic gravitational forces on galactic disks, inducing warps. They systematically compared control galaxies without warps to warped galaxies, rigorously examining the distribution bias of satellite galaxies around the central galaxies.

As a result, they found that the distribution of satellite galaxies around warped galaxies showed a distinct directional bias compared to the control group. This provides the most direct and statistically robust observational evidence supporting the idea that asymmetric dark matter halos are a primary cause of warp formation.

The asymmetry of the dark matter halos was found to be aligned with the filaments of the surrounding cosmic large-scale structure. In S-shaped warped galaxies, the halo axis was nearly parallel to adjacent filaments, while in U-shaped warped galaxies, it was almost perpendicular.

This suggests that the structures of individual galaxies on the scale of hundreds of thousands of light-years are continuously connected to the large-scale structures spanning billions of light-years. The study proposes a causal chain that links the macroscopic environment (filaments) to the properties and orientation of dark matter halos, and further to the local galactic structures (warps and satellite distributions).

A representative from Sejong University stated, "We have established an indirect measurement framework to estimate the shape and orientation of dark matter-which cannot be directly observed-through the observable distribution of satellite galaxies and disk geometry. This provides a clue for interpreting the influence of dark matter, one of the core mysteries of modern cosmology, on the evolution of galaxies and the universe from both macroscopic and microscopic perspectives."

This content was produced with the assistance of AI translation services.